Manufacture of sulfuric acid.



50 sjrption iii walter.

VUNITED STATES PATENT OFFICE.

TO HARRY EAST MLLER, OI" OAKLAND,

CALIFORNIA,

BIANUFACTURE OF SULFURIC ACID.

sucesora.

Tuill whom it may concern:

Bi'tEnougp that I, Fnsosnlcx Gsnnusn Correnti, a icitizen of 'the UnitedStates, residing et Berkeley, "QAlitlIreda county, State of California, have in vented ceritainhw and useful Improfyements in the Mannino tmobi S'ulfnrc Acid; and Ihereby declare the followingfto be o. full, clear, and ex'act description of the suine. lyiinvention relates to the manufacture o! suiuric sciili'od'espccially to that method which involves the combination oi water with sulfur trioxid, as pre the so-colled Contact method It is tvell known that when sulfur trioxid in gaseous rindiluted with inert gases such as oxygen and nitroallowed to bubble through water or dilute sol- 1 5 furie the originally clear, transparent gos is transfoifdxto a denso white cloud, (that is, a log or inist) whclllhasproved very diilicult to absorb or collect by the"driliisiry technical methods oi gas scrubhng. "Th'iisiled to the employment of streng suliuric scid .as i absorbent but considorube mechanical d ifiiculty has 'arisen from this in operations on a large scale, chiefly duciltothe size of thefabsorbing a paratus required,

with the detei'iv ration oi the materials of coniisizrutoii.; Y

invention. consists in producing in the contact gases after coming from the contact mass, liquid particleiliosnlfuric acid representing substantially l the ,gliele of the sulfur'trioxid formed in said gases by the Contact mass, 'by suitably varying the humiditynnd temperature of said gases, and, in subsequently sepaand collecting the liquid purticlesof sulfuric acid rgMyprocessri distinguished from former practice, in thatno attempt is made to directly absorb the gaseous 'sulfutrioxid; but, on the. contrary, `the gas is brought 9 5 in with water vapor for the avowed purpose of ,dipgoducing the fog or mist, which most oi the existing pros seek, in general, to avoid.- The essential and fundsmentaloonditibn recognized by the present process, .'pihetiertho contact gases be treated with water in N iy'ifomr, otros, a substitute thereor, dilute sulfuric scid',='iisthet'tlie water or dilute acid will rapidly give off aqueous ypor to the gaseous space, which vapor herejunitcs in thegaseons phase with the sulfur trioxid -.tpglorm sulfu tnliquid purticles,i'the temperature is not too high.

l aehure that the above mentioned fog or mist is 'attributed by Ysonne authorities toV the formation of a f second modification of the sulfur trioxid itself, rather Y than to sulfuric acid, on `account of its difficulty of ab- 'Ho'v'veven I consider it much more likely to be largely, at least, Inode up of sulfuric acid; and this term will be used generically in the present 'specication to designate the aggregate composition of the mist or fog. All that is'here claimed under #his ric scid which is immediately condensed Speci'caton of Letters Patent.

Application filed January 4,18%, Serial No. 294,523.

Patented Sept, 24, 1907.

term sulfuric acid is also truc ii part of those particlcs of inist consist of solid or liquid sulfur trioxid.

If the proportion of :iqucous vapor is suicient to form ordinary sulfuric :wid of H1055 or less, these particles Will have n practically iluipprcciuble vapor tonsion as regards sulfur trioxiil or sulfuric acid, and will oniybc :tbsorlicd by liquids, in so for ns they nrc brought by purely mechanical mucous inte actu-ul contact with them, there being no longer any chance for gaseous diffusion to assist the process. This is the explanation of ille failure of the ordinary scrubber methods in thc case of this mixture. Y

in carrying' out my process, the original gases containing the sulfur trioxid are cooled to s. moderato telnperature, and are thou either bubbled through, led over, nr sprayed with water, or with dilute sulfuric :tr-id, to such un extent Lhot the iiroilcts of mist formed will have the desired cmnposition, which in practice will probably he chosen not iur oin: 100% ordinary sulfuric acid. The choice of this coinpobiion will depend, among other things, upon the purpose to Vwhich the lumi product is to be put, the uses to which the residual gas is to be put., and questions of resistance of the materials of construction of the apparatus toward acid of varying composition. The finc liquid particles A of sulfuric acid which compose thc inist are separated and collected in any suitable manner. as, for example, :is iollowsz-The whole mixture, which contains disseminated through it, the sulfuric acid in the form ofvv tine liquid particles, is then subjected to centrifugal action, whereby said particles are seperated from said mixture, und con be collected. In order to illustrate this, l show in the accompanying drawing one form of :in apparatus in which the mixture muy be subjected to centrifugal action, and the fine particles of sulfuric acid separated, collected and discharged.

In the drawing the figure is'a apparatus.

A is a pipe to deliver the gases, with suspended mist or fog, to the shell G, which shell has impervious or solid walls and is mounted in suitable bearings D, in order to have imparted to it u rotary motion about its axis, by the application of suitable power, indicar/ed by the belt M,

B is the escapo pipo for the gases. v K The pipes A und B are held stationary by any suitebie means; and, in order to provide a. gas tight connectinn between them and the rotating shell C, there is a liquid seal, which may be briefly described as comprising, at the top, a foot Harige a on pipe A, lying between und slightly seperated from spaced fiangesc and c on the inner surface c* the shell C; and, at the bottom, a head flange b ou pipe B, lying above and slightly separated from an inner flange c2 on the base vertical section of the 

